Sky Router and Zyxel 1210-12 Slow speeds after router,. and wifi routing issue

[Mad-bob]

So I have Sky FTTP 1GbS connected to my Sky Router (SR203), which is then connected to a Zyxel 1210-12 Switch via a Cat 6 cable. 

Average speed at Router is 800MbS+, at the Switch I am lucky to get 350MbS and further around the house the speed can drop below 100MbS

Distance between router and switch is 2m cable.

My question is what causes the huge drop in speed between the router and switch? and whats the best way to resolve this?

As a secodary question why cant I reach a home hosted site from the wifi but its ok via a wired connection?

Thanks in Advance

[mae-3]

@Mad-bob 

Sky routers and equipment don't play nicely with managed ethernet switches, unfortunately.

But one should ensure the cables are good for sub 100Mbps it is more likely the cabling. Also, ensure one has QoS setup correctly on the ethernet switch or completely disable QoS for best performance unless it is needed.

[Chrisee]

@Mad-bob in addition if you have hard wired Sky Q tv boxes these can restrict ethernet speeds on the network.

[TimmyBGood]

@Mad-bob 

If you have the connection from the Hub to the switch running over one of those 2.5Gbs ethernet ports, I'd suggest not doing so.

As noted above, counterintuitively a simple unmanaged gigabit switch may well be 'better' than that rather overcomplicated device for home use.

[Mad-bob]

With thanks to @mae-3 @Chrisee and @TimmyBGood for their replies, I thought I wou/ld post an update to whats happend and what solution I have come up with.

As @Chrisee mentioned, the Sky boxes do not play nice with network gear and in particular appear to really hate my powerline setup! After direct connect of my 2 switches I started to hit more normal speeds of 600+ MbS from the second switch (under my TV ) to the desk and then out to the internet. Im hitting 700+ MbS from the desktop switch out to the net. I will interconnect these switches with fiber and see if that makes any improvement.

In the mean time I have returned all the upstairs Sky boxes and TV's to Wifi to allow connection, which has reduced the performance of the wifi a bit, but I am hloping thats due to the amount of traffic the router is handling.

TL:DR 

Removed powerline setup got an instant improvement to speeds across the entire network going to try fiber between switches. All Sky boxes and TV's are now wifi enabled.

[Chrisee]

@Mad-bob Powerline performance is influenced by the condition and topology of your mains wiring which is a more likely issue. My oown Devolo 1200 units have halved in speed from offering over 400Mb/s when new to around 200Mb/s now and I no longer have Sky Q.

However Q boxes actually do not need or indeed can use high network speeds. The Sky Q system was developed around 2015 using some clever but early mesh networking systems. These are beginning to present issues as home networks get faster. As an example the latest Sky hub the SR213 and its dedicated extenders in the Wifi Max bundle are currently incompatable with Sky Q.